A significant percentage of dengue patients develop Dengue Shock Syndrome (DSS) which is characterized by increased vascular permeability, circulatory failure and often death. Montelukast, a cysteinyl leukotriene receptor antagonist regulates vascular permeability and we hypothesized that it may be effective in protecting against DSS. An open label, parallel, randomized controlled trial (RCT) was thus carried out at Mayo Hospital, Department of Medicine, Lahore. A total of 200 patients of dengue fever were recruited and randomized into two groups. The group A was treated with Montelukast 10 mg once daily for 5 days along with general supportive treatment. Group B received the standard supportive treatment and served as the control group. The frequency of DSS was compared in the two groups by Chi square test. A binary logistic regression analysis was conducted to assess the effects of montelukast treatment on onset of DSS after adjusting for gender, age, white cell count, platelet count, haematocrit, serum alanine transaminase (ALT) and aspartate transaminase (AST). Relative risk (RR), absolute risk reduction (ARR), relative risk reduction (RRR) and numbers needed to treat (NNT) were calculated. Significance level was set at p0.001, Odds ratio=5.01, 95% CI=2.17-11.60) even after adjusting for confounders. Montelukast reduced the absolute risk (ARR=22%) and the relative risk (RRR=71%) of DSS in dengue fever. Numbers needed to treat were 4.55. We thus conclude that treatment with oral montelukast may protect patients of dengue fever from DSS and greatly reduce mortality.
Background: Countries across Africa and Asia have introduced a variety of measures to prevent and treat COVID-19 with medicines and personal protective equipment (PPE). However, there has been considerable controversy surrounding some treatments including hydroxychloroquine where the initial hype and misinformation led to shortages, price rises and suicides. Price rises and shortages were also seen for PPE. Such activities can have catastrophic consequences especially in countries with high co-payment levels. Consequently, there is a need to investigate this further. Objective: Assess changes in utilisation, prices, and shortages of pertinent medicines and PPE among African and Asian countries since the start of pandemic. Our approach: Data gathering among community pharmacists to assess changes in patterns from the beginning of March until principally the end of May 2020. In addition, suggestions on ways to reduce misinformation. Results: One hundred and thirty one pharmacists took part building on the earlier studies across Asia. There were increases in the utilisation of principally antimalarials (hydroxychloroquine) and antibiotics (azithromycin) especially in Nigeria and Ghana. There were limited changes in Namibia and Vietnam reflecting current initiatives to reduce inappropriate prescribing and dispensing of antimicrobials. Encouragingly, there was increased use of vitamins/immune boosters and PPE across the countries where documented. In addition, generally limited change in the utilisation of herbal medicines. However, shortages have resulted in appreciable price increases in some countries although moderated in others through government initiatives. Suggestions in Namibia going forward included better planning and educating patients. Conclusion: Encouraging to see increases in the utilisation of vitamins/immune boosters and PPE. However, concerns with increased utilisation of antimicrobials needs addressing alongside misinformation, unintended consequences from the pandemic and any appreciable price rises. Community pharmacists and patient organisations can play key roles in providing evidence-based advice, helping moderate prices through improved stock management, and helping address unintended consequences of the pandemic.
When Darwin visited the Galapagos archipelago, he observed that, in spite of the islands' physical similarity, members of species that had dispersed to them recently were beginning to diverge from each other. He postulated that these divergences must have resulted primarily from interactions with sets of other species that had also diverged across these otherwise similar islands. By extrapolation, if Darwin is correct, such complex interactions must be driving species divergences across all ecosystems. However, many current general ecological theories that predict observed distributions of species in ecosystems do not take the details of between-species interactions into account. Here we quantify, in sixteen forest diversity plots (FDPs) worldwide, highly significant negative density-dependent (NDD) components of both conspecific and heterospecific between-tree interactions that affect the trees' distributions, growth, recruitment, and mortality. These interactions decline smoothly in significance with increasing physical distance between trees. They also tend to decline in significance with increasing phylogenetic distance between the trees, but each FDP exhibits its own unique pattern of exceptions to this overall decline. Unique patterns of between-species interactions in ecosystems, of the general type that Darwin postulated, are likely to have contributed to the exceptions. We test the power of our null-model method by using a deliberately modified data set, and show that the method easily identifies the modifications. We examine how some of the exceptions, at the Wind River (USA) FDP, reveal new details of a known allelopathic effect of one of the Wind River gymnosperm species. Finally, we explore how similar analyses can be used to investigate details of many types of interactions in these complex ecosystems, and can provide clues to the evolution of these interactions.
The growth and survival of individual trees determine the physical structure of a forest with important consequences for forest function. However, given the diversity of tree species and forest biomes, quantifying the multitude of demographic strategies within and across forests and the way that they translate into forest structure and function remains a significant challenge. Here, we quantify the demographic rates of 1,961 tree species from temperate and tropical forests and evaluate how demographic diversity (DD) and demographic composition (DC) differ across forests, and how these differences in demography relate to species richness, aboveground biomass, and carbon residence time. We find wide variation in DD and DC across forest plots, patterns that are not explained by species richness or climate variables alone. There is no evidence that DD has an effect on either aboveground biomass or carbon residence time. Rather, the DC of forests, specifically the relative abundance of large statured species, predicted both biomass and carbon residence time. Our results demonstrate the distinct demographic compositions of globally distributed forests, reflecting biogeography, recent history, and current plot conditions. Linking the demographic composition of forests to resilience or vulnerability to climate change, will improve the precision and accuracy of predictions of future forest composition, structure and function.
Arbuscular mycorrhizal (AM) and ectomycorrhizal (EcM) associations are critical for host-tree performance. However, how mycorrhizal associations correlate with the latitudinal tree beta-diversity remains untested. Using a global dataset of 45 forest plots representing 2,804,270 trees across 3840 species, we test how AM and EcM trees contribute to total beta-diversity and its components (turnover and nestedness) of all trees. We find AM rather than EcM trees predominantly contribute to decreasing total beta-diversity and turnover and increasing nestedness with increasing latitude, probably because wide distributions of EcM trees do not generate strong compositional differences among localities. Environmental variables, especially temperature and precipitation, are strongly correlated with beta-diversity patterns for both AM trees and all trees rather than EcM trees. Results support our hypotheses that latitudinal beta-diversity patterns and environmental effects on these patterns are highly dependent on mycorrhizal types. Our findings highlight the importance of AM-dominated forests for conserving global forest biodiversity.